Spinal implants such as interbody fusion devices are used to treat degenerative disc disease and other damages or defects in the spinal disc between adjacent vertebrae. The disc may be herniated or suffering from a variety of degenerative conditions, such that the anatomical function of the spinal disc is disrupted. Most prevalent surgical treatment for these conditions is to fuse the two vertebrae surrounding the affected disc. In most cases, the entire disc will be removed, except for a portion of the annulus, by way of a discectomy procedure. A spinal fusion device is then introduced into the intradiscal space and suitable bone graft or bone substitute material is placed substantially in and/or adjacent the device in order to promote fusion between two adjacent vertebrae.
One embodiment of a spinal fusion device is described in U.S. Patent Publication No. 2015/0202051, entitled “Spinal Fusion System”, filed on Jan. 16, 2015 by Shigeru Tanaka et al. (the '051 Application) and assigned to the same assignee as the subject application. The spinal fusion system described in the '051 Application includes an interbody fusion cage, a fixation plate, and an implanter. The fixation plate is receivable in an open volume of the interbody fusion cage and includes a superior blade and an inferior blade. The fixation plate is displaceable between a non-deployed state and a deployed state, wherein, when the fixation plate is received in the open volume and the fixation plate is in the non-deployed state, the superior and inferior blades extend generally parallel to each other. When the fixation plate is in the deployed state, the superior and inferior blades extend oppositely from each other into the endplates of opposing vertebral bodies. In a particular arrangement, the system may further include a trial/sizer tool including a set of trial/sizer instruments. Such instruments may incorporate a pre-scoring blade to break the vertebral endplate prior to insertion of the spinal implant into the disc space and deployment of the blades into the endplates. Thus, a trial device may serve two purposes, namely to test a size for a potential interbody fusion cage implant and to prepare one or more vertebral endplate surfaces for receiving the implant. The entire contents of the '051 Application are incorporated herein by reference.
While a trial device with a pre-scoring blade is beneficial, a system having the capability of precisely correlating the entry location of an anchor blade into the vertebral endplate of one or more vertebral bodies with the pre-scored location of such endplates is desirable.